During the first and second centuries of the Common Era the Christ cult spread from rural Palestine to the large cities of the Empire. This article draws insights from social network theory and from epidemiology, arguing that the Christ cult was not a simple contagion, spread by simple contact, but a ‘complex contagion’ that required persuasion, especially because adherence to the Christ cult entailed potential social costs and demanded high signalling costs.

1 John 1.9 and 5.16 reflect practices of public confession of sins, intercession, and mediation of God's forgiveness. Divine forgiveness and belonging to the community were integrated in the Johannine community to the extent that one equalled the other. Therefore, these practices had important group-dynamic functions for the Johannine community. First, public confession functioned as a costly signal that deterred less committed group members but was meaningful to committed group members. Second, the practice of intercession induced role taking, allowing the offended party both to empathize with the offender and to restore his or her dignity and honour.